Cap for flasks



(No Model.)

. w.- 0. JOHNSON. GAP FOR FLASKS, &c.

No. 340,443. Patented Apr. 20, 1886.

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NITED STATES.

WILLIAM C. JOHNSON, OF PHILADELPHIA, PENNSYLVANIA.

.CAP FOR FLASKS, 84C.

SPECIFICATION forming part of Letters Patent No. 340,443, dated April 20, 1886.

Application filed February 26, 1886. Serial No. 193,308. (No model.)

To all whom it may concerm Be it known that I, \VILLIAM O. JOHNSON,

a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Caps for Flasks, &c., of which the following is a specification.

The object of my invention is to provide a screw-cap for pocket-flasks and like vessels with a cheap packing which will effectually prevent leakage, irrespective of the inequalities in the seat formed by the mouth of the flask or of defects in the cork stopper.

In the accompanying drawings, Figure 1 is a side view, on an enlarged scale, of a pocketflask having a screw cap with packing in ac cordance with my invention, the neck of the flask, the cap, and the packing being in section; and Fig. 2, a perspective View of the cap and tie packing detached therefrom.

In making cheap grades of pocket-flasks it is the practice to roughly grind the mouth to remove the fin left-0n breaking off the blowover; but no attempt is made to render the mouth true, as this would require the exercise of greater care and skill than is warranted by the price at which the flasks are sold.

In consequence of the rough and uneven mouth presented by the flask, the thin cork disk with which the screwcap or cover of the flask is provided fails to make a joint sufficiently tight to prevent leakage, and it is mainly with the view of overcoming this ob.- jection that my inventionhas been devised.

I provide the screw-cap a with the usual internal disk, I), of cork,which rests upon and closes the mouth of the flask, but between said disk and the top of the cap I interpose a rubber washer, d, preferablydbrthe sake of economy, made in the form of a ring, as shown in Fig. 2. This washer forms such an elastic backing for all portions of the disk D that are subjected to pressure that when the cap is screwed down on the threaded neck of the flask the cork disk is permitted to yield at any point owing to this elastic backing. and is thus pressed firmly into contact with all portions of the seat formed by the mouth of the flask, however rough and uneven this seat may be, leakage being thus effectually prevented.

The cork disks or shavings used as stoppers for this class of flasks are frequently defective in that they have small perforations which reuder the stopper leaky. however, that when the stopper is backed by an elastic washer, as in my improved cap, there can be no leakage from this cause, as any liquid which may find its way through the cork-disk is prevented from escaping, owing to the tight joints formed between the washer and the cork and cap. I

I am aware that a rubber, ring has been interposed directly between a cap and seat, so as to serve as a packing for a fruit jar orsimilar vessel; but rubber rings cannot be used in this way in a liquor-flask-such as that for which my improved cap or stopper is intended-as they would not only taint the liqnor, but would be rapidly destroyed by the action of the latter.

I am also aware that an inkstand or like vessel has been provided with acap having an internal disk of cork backed by a coiled spring; but such a spring acts uniformly upon all portions of the disk, and does not permit the yielding of one portion of the disk independently of another portion; hence the disk cannot accommodate itself to inequalities in the mouth, nor does such coiled spring prevent leakage in the event of the cork disk being defective.

I therefore claim as my invention The within-described cap or stopper for flasks, said cap consisting of the outer metallic shell, the internal flexible disk for closing the mouth of the flask, and a flat rubber washer interposed between the disk and the top of the cap and providing a-uniformly elastic backing for that portion of the disk which is caused to bear upon the mouth of the flask, whereby said disk is free to yield to accommodate itself to inequalities in the month, all substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

XVILLIAM O. JOHNSON.

It will be evident, 

